Productive reuse of wastes & wastewater

The RUAF Foundation, with its international and local partners and specifically its member organisation IWMI, explores innovations on the agriculture, water and energy nexus, supporting the inclusive transitioning to (more) resource efficient cities. RUAF facilitates increased reuse of solid and liquid wastes in (intra- and peri-) urban agriculture through applied research, development of safe reuse practices, staff training, assisting in the design of municipal resource recovery strategies and programmes, stimulating innovation in the agriculture-water-energy nexus and documenting best practices and business models that combine productivity with reduced environmental impacts.

Urban agriculture is part of the urban ecological system and can play an important role in urban environmental management. It is acknowledged that environment, water, sanitation and hygiene issues need to be seen in relation — as a nexus —to areas such as health, food security, energy and economic growth. There are multiple links between improving urban wastewater management, household sanitation, solid waste management and the safe and productive use or urban organic wastes and wastewater in (intra- and peri-) urban agriculture. Taking such a nexus perspective helps to identify drivers and enabling factors that would otherwise be overlooked, and can create synergies.

As competition for water in densely populated zones intensifies, producers close to cities increasingly make use of wastewater for irrigation in agriculture and aquaculture. Productive reuse of waste water in urban agriculture has the potential to reduce the demand for freshwater supply as well diminish the discharge of untreated waste water into rivers, canals and other surface water sources. Where only partial or no wastewater treatment is available, the health risks of productive reuse of waste water can be reduced through complementary health risk reduction measures as explained in the new WHO guidelines for safe use of excreta and wastewater.

Decentralised collection and composting of urban organic wastes presents opportunities to reduce the costs of public waste management, while large quantities of nutrients are reclaimed and productively reused in urban agriculture.  Composting organic wastes and the reuse of faecal sludge as an alternative nutrient source for agricultural production will reduce the demand for finite mineral resources (like phosphorus) and the energy requirements for producing related artificial fertilisers. Moreover enhanced recycling of urban organic wastes will reduce methane emissions from landfills. Organic wastes may also be used as a source of energy by incineration in an electricity- producing plant, biogas production capturing methane emission from organic wastes and sewage sludge, or by making briquettes from organic wastes for household use.
Urban areas are hot spots for various resource recovery options and provide good opportunities for reaching scale in sustainable reuse of the recovered nutrients and water in intra- and peri-urban agriculture (and other sectors as well).

The RUAF Foundation and its partners IWMI and WASTE are working on this interface of agriculture, water and sanitation (including solid waste) to develop sustainable solutions for growing cities. In RUAF projects local authorities, urban producers and other entrepreneurs, and other stakeholders are brought together in a multi-stakeholder innovation process for the development of waste management practices and businesses that combine productivity with reduced environmental impacts and costs, and adequate monitoring.  
The RUAF Foundation assists municipalities, urban producers and other stakeholders to increase the reuse of urban solid and liquid wastes in intra- and peri-urban agriculture through applied research, development of safe reuse practices, staff training, and documenting best practices and business models that combine productivity with reduced environmental impacts.  RUAF and local partners seek to develop urban sanitation systems that include safe and productive use of solid wastes and wastewater and undertakes research to determine to what extent localised food production and short food chains can provide opportunities to prevent and reduce food losses and food wastes.

Examples of such projects include:

  • WASH: In the context of the Dutch WASH Alliance, RUAF facilitates the integration (into WASH water and sanitation projects) of safe reuse in agriculture of wastewater (including household grey wastewater) and organic wastes (including human excreta) in city regions in Ghana, Nepal, Kenya, Ethiopia and Bangladesh.
  • SWITCH: As part of the SWITCH programme the RUAF Foundation developed innovations in waste water treatment and productive reuse of urban water (including storm and wastewater) in urban agriculture in Beijing, Accra and Lima
  • SUPURBFOOD: RUAF prepared an overview of successful cases of resource recovery and productive reuse of organic wastes and wastewater in urban agriculture and organized an exchange between Northern and Southern organisations involved in this programme
  • The Urban agriculture for food security projects in Liberia, under which  RUAF amongst others supports work on EcoSanitation and productive reuse in urban agriculture with Welthungerhilfe and the Monrovia Municipality and coordinates a study on related food safety aspects
  • The GlobE-UrbanFoodPlus programme that develops innovations for resource recovery and resource-use efficiency in urban agriculture in four West African cities.
  • The study on reduction of food wastes undertaken by RUAF member organisation IGSNRR in China
  • The staff training courses on the productive use of organic waste and wastewater in urban agriculture implemented by RUAF

More information on rural-urban resource flows, opportunities of resource recovery from solid waste and wastewater, assessments and mitigation of related health risks can be found on the website of RUAF member organisation IWMI as part of their sub-programme on Resource Recovery & Reuse